Our studies will concentrate on two proteins which are involved in the process of DNA replication. One of them, the dnaG protein in known to synthesize "primers" for Okazaki fragments. The polymerization capacity and general biochemical properties of the enzyme-substrate will be studied. We will concentrate on the further characterization of a recently discovered helicase (helicase III). This enzyme can participate in DNA unwinding in vitro. We would like to determine what its function is in vivo. This will be done by the isolation of mutants defective in DNA replication. The screening will be done by optimizing for helicase mutants.